Scaup

Aythya marila

42-51cm

Appearance

This diving duck is bulkier than many of its counterparts. It can appear similar to the Tufted Duck, but the Scaup has a more rounded head and is without a tufted crown. It is broad-bellied and its wide bill has a fine black tip. The sexes are dissimilar; the male has a black head and neck which is green-glossed in the right light. Intricate barring is seen on his back, and his flanks and belly are white, his stern black. He has a piercing yellow eye and a grey bill. The female is predominately brown, palest on her flanks. She has a characteristic white smudge at the base of her bill and a pale buff mark on her cheek. Juvenile is like the adult female but the patch around the bill is thinner and less obvious. When flying, the Scaup has a thick white wingbar.

Habitat

This bird is primarily a marine dweller, found in estuary mouths, and sheltered coasts and bays. Due to its feeding habits, it will always be in a place where bottom-dwelling invertebrates are readily available.

Character

Moves in flocks for majority of the year, and the ratio of males to females varies; more males can be found in the north, and more females in the south. Flocks can be large, with hundreds or even thousands of birds. This bird is rarely seen on land; it dives regularly and swims quite low in the water.

Food

Relies mostly on shellfish, the blue mussel in particular, but it also eats cockles, periwinkles and small marine snails. Diets also includes insects, crustaceans and plant material.

Breeding

Nests are built on the ground close to water and hidden by vegetation; they nest individually or in colonies, not uncommonly amongst those of terns and gulls. The female lays 8-11 eggs and incubates for approximately 26 days; the male usually deserts during this time. Young fly after about 40 days and remain with the female until this time and sometimes beyond.

Population

This species is best known as a winter visitor from breeding territories in Iceland and Scandinavia; the last estimate was 16 500 birds in Britain and Ireland in late October. The birds remain until February and March, though some young stay through the following summer. Numbers of birds are decreasing by an estimated 50% in the last 25 years.

Observation Tips

This bird used to be found near coastal sewage or other marine dumps, but since environmental measures have been taken, the population is less predictable.

Voice

Mostly a silent bird, but during courtship the male can utter a gentle call similar to a dove's. The female has a soft, deep growl.